For the guest user, they get to use your Chromebook without worrying about leaving any trace of their browsing session on your Chromebook.

Here is a video explaining the guest mode:

You need to enable Guest Mode on your Chromebook to use this feature.

Enable or disable guest browsing

Sign in to the Chromebook owner’s Google Account.

Click the status area in the lower-right corner, where your picture appears.

Select Settings and find the “Users” section.

Click Manage other users.

Check or uncheck the “Enable guest browsing” checkbox to control the feature.

Logging Into Guest Mode

To start a guest browsing session, select Browse as Guest from the launcher. When you’re browsing as a guest, you can browse the web and download files as usual, though you won’t be able to install apps unless you sign in to the Chromebook with a Google Account.

Missing Things

You will not get some stuff on the guest mode Here is a list:

Extensions: Extensions installed by the Chromebook owner won’t be available

Apps will not be available other than the basic apps (Files app is available.)

You cannot change the default wallpaper

To end a guest browsing session, select Exit guest (or use the keyboard shortcut Ctrl+Shift+Q) to end your guest session. Your browsing data won’t be saved, but keep in mind that some websites may still have records of your visit.